1. Field of the Invention
The invention relates to a drive device for a swivelling component which is pivotally mounted preferably on a motor vehicle. The swivelling component is connected to the drive via a coupler which can be swivelled by the drive. The coupler has a connector that is connected via a connecting rod to the swivelling component. The connector can be driven by the drive and is movably supported along a guideway.
2. Description of Related Art
Actuating the swivelling components on a motor vehicle, such as for example the swivel bearing of a folding convertible top, via a hydraulic drive with a hydraulic cylinder and via an electric drive with toothed gearing, is known. These drive devices, however, are characterized by a complex design, high cost, large required installation space and/or by loud motor noise in the electric motor which is located in the vicinity of the vehicle passengers. Moreover, the lever arm changes during the swivelling motion so that the transmitted drive torque varies, and the swivel angle is ordinarily structurally limited to less than 180xc2x0 in a hydraulic drive.
The object of the invention is to devise the initially named drive device with a simplified structure and improved mode of operation.
This object is achieved in the initially mentioned drive device with a guideway that is a circular arc-shaped guide rail with the center of the circle lying on the axis of rotation of the swivelling component or being formed as a three-dimensional curve. Thus, in this drive device, as a result of the uniform distance of each point on the guideway to the swivel axis, uniform drive motion is converted into uniform motion of the swivel component. Thus, a complicated transmission mechanism for the drive motion is unnecessary.
The drive force and the drive motion will be routed via the connector to the guideway which can be supported to move on the guideway or is movably held by another component which forces it to follow the guideway.
In one preferred embodiment the coupler contains a drive cable which is routed in a tube to the guideway and is connected to the connector. The drive cable enables arrangement of the drive motor both near the swivelling component or the guideway and also away from it, and, thus, offers additional installation positions in the motor vehicle which are largely independent of the position of the swivelling component. Thus, the audible operating noise of the drive motor can be reduced by an insulated position and/or a position which is away from the passengers, as is known of the drive motors of sliding roofs which are accommodated away from the actuating mechanism of a cover to be opened on a front cross member or in the trunk. The drive cable which is guided in the tube can transmit both tensile and also compressive force and can be guided on largely any path in the body. The drive cable can be guided to two swivelling components which can be actuated in synchronism or two drive cables are synchronously driven by means of a rack.
Due to its bending capacity the drive cable can also follow curved guideways. A section of the drive cable which runs beyond the guideway can be connected to other components and thus can execute additional motion functions. The drive device, thus, contains only a few components and can be housed within a small installation space in the motor vehicle.
Since the circular arc-shaped guide rail has a constant radial distance to the axis of rotation of the swivelling component over the swivelling path and also a drive cable follows this guideway, the drive force and the drive motion of the drive cable are transmitted uniformly to the swivelling component. Angles of rotation up to roughly 360xc2x0 can be accomplished with the circular arc-shaped guide rail.
One alternative configuration calls for the guideway to be formed as a three-dimensional curve which deviates from a plane circular arc guide. Thus, largely any transfers of motion on the drive device can be carried out, and also additional functions of the drive cable can be controlled which, for example, can be executed by coupling the components on the three-dimensional path of motion of the guideway. Feasibly, the connecting rod is then pivotally mounted on the swivelling component around a swivel axis which is roughly perpendicular to the swivel axis of the swivelling component in order to follow the three-dimensional curve when the drive motion is transmitted to the swivelling component. In doing so, it can be advantageous if the connecting rod is variable in length and can be matched to the changing distance between the axis of rotation of the swivel component and the connector on the guideway of the three-dimensional curve.
Feasibly, the swivelling component and the guideway or guide rail are supported on a vehicle-mounted main bearing so that a compact unit is formed.
Preferably, the connector is a cable linkage which is held in the guide rail in a guide channel for the drive cable, reaches to the outside through a lengthwise slot and is connected to the connecting rod. For mutual matching it is feasible for the cable connecting part to be matched to the curvature of the guide rail.
In order to prevent pinching of the drive device, the circular arc-shaped guide rail can be supported with play on the main bearing, or the play can be balanced on the linkage to the swivelling component. The play is fixed such that when a part which is moved by the swivelling component, for example the folding convertible top twists the radial distance from the axis of rotation of the swivelling component to the cable linkage remains essentially constant.
It can be provided that additional actuation by the drive device can be done. An end section of the drive cable with a component to be actuated can be connected for additional actuation.
The drive can be an electric motor or several series connected electric motors. But fundamentally also hydraulic or pneumatic motors which act for example on a sliding element in the guide rail are also suitable.
The drive device can be coupled to a windshield wiper, especially the rear windshield wiper of a motor vehicle. In one preferred application, it is coupled to a folding convertible top. The swivelling component being the main column of a parallelogram-like four-bar mechanism for swivelled support of the rod assembly of the folding top, and the four-bar mechanism contains the main column and a main connecting rod which, on the one hand, are pivotally mounted on the body-mounted main bearing and, on the other hand, on a lateral roof rod of the rod assembly of the top. For synchronous drive of the right-side and left-side main column it is then a good idea if the drive cable at the same time drives the two swivelling components or the main columns.
These and further objects, features and advantages of the present invention will become apparent from the following description when taken in connection with the accompanying drawings which, for purposes of illustration only, show several embodiments in accordance with the present invention.